510 PROFESSOR CHALLIS, ON THE DETERMINATION OF THE LONGITUDE 



Fourth Set — continued. 



Fourth Set — continued. 



Notes. 



Nos. 11 and 40, the Cambridge times have been increased 1*. (See the observations). 

 No. 48, the Greenwich time has been corrected by + ]'. No. 72, the Cambridge time has 

 been corrected by + I s . No. 97, the Cambridge time has been corrected by + 2 s . 



The mean results given by the several sets and by the sets collectively are as follows : — 



May 17. 



No. of 

 signals. 



First set (I.) 26 . 



Third set (III.) 34 . 



(I.) + (III.) 60. 



Mean. 

 ». 



22,895 



23,062 



No. of 

 signals. 



... 22,990 



Mean from all the sets = 22 s ,992. 



Second set (II.) 41 



Fourth set (IV.) ... 45 



(II.) + (IV.) ~86 



Mean. 



$1 



23,002 



22,984 

 22,993 



No. of 

 signals. 



First set (I.) 31 



Third set (III.) 27 



(I.) + (III.) 58~ 



May 18. 



Mean. 



t. 



23,004 



23,161 



No. of 

 signals. 



... 23,078 



Mean from all the sets = 23 s ,032 



Second set (II.) 37 



Fourth set (IV.) ... 40 



(II.) + (IV.) 77 



May 17, Excess of (I.) + (III.) above (II.) + (IV.) = - 0,003 

 18 =+0,081 



Mean. 

 jr. 



22,999 

 22,995 



22,997 



Mean = + 0,039 



